|
Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
|
Thread Tools |
4th Nov 2020, 8:38 am | #81 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Finally some progress on the jammed tuner cap! Last night I did these two things:
1.Sprayed the cap fins with non residue contact cleaner followed by a blow out with compressed air (had the rest of the area covered with tissue to catch the overflow) 2. Added WD40 to the bearing points where the cap axle runs through the chassis. Had been trying light oil and silicone lubricant before but this only helped for a short while. But after the approach above I now, 12 hours later, still have an easy moving tuner that also works with good reception and stations where they should be on the scale. Just wonder now if I should leave the wd40 in or try to clean it out and ad other type of lubrication? |
4th Nov 2020, 9:28 am | #82 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,830
|
Re: Trying to revive a Goodmans One Ten receiver
If it's working as you describe, then leave well alone.
__________________
A digital radio is the latest thing, but a vintage wireless is forever.. |
4th Nov 2020, 9:43 am | #83 | |
Octode
Join Date: Jan 2003
Location: Ware, Herts. UK.
Posts: 1,082
|
Re: Trying to revive a Goodmans One Ten receiver
Quote:
John |
|
4th Nov 2020, 9:57 am | #84 | ||
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Quote:
|
||
4th Nov 2020, 10:22 am | #85 |
Guest
Posts: n/a
|
Re: Trying to revive a Goodmans One Ten receiver
The 100uA meter is just twice as sensitive if yours really is 200uA. I would have thought you would just need a series resistor. Attached pic is showing what your measured 0.17V would display on this meter with a 1K series resistor.
Arthur |
4th Nov 2020, 11:14 am | #86 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Looks like a nice, doable fix . As posted before, I´ll do some measuring of my broken meter and get back to you regarding the offer.
|
4th Nov 2020, 12:50 pm | #87 |
Guest
Posts: n/a
|
Re: Trying to revive a Goodmans One Ten receiver
I should really have given you the dimensions of this meter! The front is 34.75x13.90mm and the overall depth is 32.32mm
Arthur |
4th Nov 2020, 1:56 pm | #88 |
Nonode
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 2,867
|
Re: Trying to revive a Goodmans One Ten receiver
Hi!
The correct way to determine the resistance of your replacement signal– strength/tuning meter is as follows:– 1) Connect a 100k resistor in series with the meter and connect the meter plus resistor across a variable supply, and adjust the voltage from the supply so the meter reads exactly F.S.D; 2) Switch off the power supply and connect a pot of about 22k across the meter to act as a shunt, and switch on the supply again. Adjust the 22k shunt pot. until the meter registers EXACTLY half F.S.D. Switch off and disconnect the power supply and shunt pot. from the meter, and then measure the value of the shunt pot. – this will be equal to the internal resistance of the meter movement! Chris Williams
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! |
4th Nov 2020, 8:39 pm | #89 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
|
5th Nov 2020, 8:34 am | #90 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Put the One Ten together last night and must say Goodmans had a feeling for style and detail putting this together. I mean: who wants to ugly up a nice reciever with headphone connector? Of course they should be under a hatch !
Video (shared gdrive): https://drive.google.com/file/d/1287...ew?usp=sharing Light working: https://drive.google.com/file/d/12I_...ew?usp=sharing Cleaned up nicely: Time to try it in my main setup and see how it stacks up against my daily driver, a JVC vr-5535l, to do some real compairing of sound quality. Got the feeling the Goodmans will hold its own well... |
5th Nov 2020, 7:50 pm | #91 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Trying out for the no1 spot in the setup together with the Garrard Zero 100 and Little Bear T10. Looking good in the cabinet! Still evaluating. Maybe the Swedish Sentec SP77 speakers are not the best match for it though....
|
6th Nov 2020, 9:42 am | #92 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
And today my dear wife inspected the One Ten in the cabinet. Passed immediate judgement:
"What a big, ugly thing! Change back to the other one at once!!!" ...so we have a bit of a domestic dispute to resolve here |
9th Nov 2020, 10:33 pm | #93 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Hi!
Another thing to check I guess is the bias adjustment. It's pretty well described in the service manual. But, I fel a bit stupid regarding where to connect the multimeter on the "supply rail". Grateful for bit of guidance with this |
10th Nov 2020, 12:06 am | #94 |
Heptode
Join Date: Oct 2019
Location: Täby, Sweden
Posts: 702
|
Re: Trying to revive a Goodmans One Ten receiver
Are we still talking about your other half’s unfounded bias against classic hifi?
|
10th Nov 2020, 12:08 am | #95 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,867
|
Re: Trying to revive a Goodmans One Ten receiver
I can't read component designators or values on the schematic.
The written procedure talks about opening power supply connections (one at a time) to each amplifier and measuring the current. Because other things take current, it has you measure with the amplifier quiescent current fully backed off, and then adjusting it to an increase of 3mA This procedure was written in the days when most workshops did not have meters that would go down to millivolts DC, but could measure milliamps. HOWEVER, this procedure is risky because one small slip while power connections are broken can destroy some semiconductors in that power amplifier, and tracking down which is a major undertaking. Several people on here have destroyed amplifiers doing this. It's especially nasty if it's one you just fixed. A more modern way relies on sensitive DC voltmeters. Most decent hand-held DVMs will dothe job. Between the collectors of the two high power transistors is a pair of resistors in series.... low value ones. With the amplifier on, but no signal, measure voltage between the two collectors. It'll be small. Take care probing. As a double check, away from the amplifier, touch both probes together and see what reading error the meter gives you with zero volts input. On the schematic, read the values of those two resistors and add them. Use Ohms law with the voltage you measured (correcting for the zero volts reading makes it more accurate) and you have the amplifier's quiescent bias vurrent in the output stage. Take care probing.... one slip is all it takes and it's kaput. But this way you don't have to disconnect wires and restore them. David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
10th Nov 2020, 6:19 am | #96 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Thanks for good advice, David.
I have a decent digital multimeter so I will try the method you suggested. Will post some pictures first to check with you so I am using the correct connection points. Will probably be a couple of days. Hahaha, spot on ! |
10th Nov 2020, 4:06 pm | #97 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
So, now I have been listening to the One Ten a bit more and find it to sound quite good but not as good as the JVC vr5535l that is my daily driver.
It sounds a bit more veiled/dull with less transparency and clearness than the JVC. I don´t know if it´s just it´s character of sound, a speaker mismatch or a case of ageing components. The only replacement I have done is the faulty transistor in the power supply and the two big reservoar caps (replaced with same specs). Regarding the speakers I am using are seventies Swedish Sentec SP77:s that have two bass elements and two tweeters each. They are spec:ed (according to a leaflet I found online): Power 50w impedance 8 ohms Sensitivity 4w I also have a pair of Boston Acoustics A60:s that I may try. They are spec:ed: Frequency Response: 55 Hz - 22,000 Hz ±3 dB Crossover Frequency: 6 dB/octave at 3000 Hz Impedance: 8 Ω nominal, 6 Ω minimum Sensitivity (at 1 watt/m input): 90 dB Recommended Amplifier Power: 10 to 60 watts per channel Are these a better match? On the matter of recap, is this a path to explore and are there any specific capacitors exept for the reservoir (already replaced) I could start looking at? Unfortunately I´m still a newbie regarding reading schematics and understanding the works of different components. But if I get some pointers on which component number to replace I can probably manage process of solder it right. The One Ten seems fortunately pretty easy to access for this kind of job. But still, I´d rather try to pinpoint a few caps than tearing them all out Here´s the service manual if anyone wants to take a peek: https://drive.google.com/file/d/1yVeIvMhRFWPxUyPCpw28FlZgEhwAUIEf/view?usp=sharing Thanks in advance for any wisdom regarding this! |
12th Nov 2020, 8:37 am | #98 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
So, I´m pondering wether to start a recap work and begin with the rest of the power supply capacitors. They seem pretty easy an straightforward to replace. Good idea?
|
12th Nov 2020, 9:37 am | #99 |
Octode
Join Date: Jan 2003
Location: Ware, Herts. UK.
Posts: 1,082
|
Re: Trying to revive a Goodmans One Ten receiver
With transistor equipment the general advice with regards to changing capacitors is that if it's working, leave it alone. There is no point in changing power supply capacitors unless you have excessive hum or another obvious fault.
This receiver does contain quite a few tantalum bead capacitors which can be unreliable, but you would be best advised to use the receiver and listen out for any unusual changes in its sound that may indicate a fault. John |
12th Nov 2020, 10:10 am | #100 |
Tetrode
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 77
|
Re: Trying to revive a Goodmans One Ten receiver
Thanks for responding, John!
As I posted above there´s no obvious fault in the sound like hum, static, pops etc. But I feel that the sound quality is a bit muffled / dull lacking som clearness. Bass can feel a bit boomy too. Was thinking this could be caused by components ageing and going out of spec? |